<?php

class JSSDK {
    private $appId;
    private $appSecret;
    private $url;
    public function __construct($appId, $appSecret, $url) {
        $this->appId = $appId;
        $this->appSecret = $appSecret;
        $this->url = $url;
    }
    public function getSignPackage() {
        $jsapiTicket = $this->getJsApiTicket();
        $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
        // $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
        $url = urldecode($this->url);
        $timestamp = time();
        $nonceStr = $this->createNonceStr();
        // 这里参数的顺序要按照 key 值 ASCII 码升序排序
        $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";

        $signature = sha1($string);
        $signPackage = array("appId" => $this->appId, "nonceStr" => $nonceStr, "timestamp" => $timestamp, "url" => $url, "signature" => $signature, "rawString" => $string);
        return $signPackage;
    }
    private function createNonceStr($length = 16) {
        $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        $str = "";
        for ($i = 0;$i < $length;$i++) {
            $str.= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }
    private function getJsApiTicket() {
        // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例
        $data = json_decode(file_get_contents("jsapi_ticket.json"));
        if ($data->expire_time < time()) {
            $accessToken = $this->getAccessToken();
            // 如果是企业号用以下 URL 获取 ticket
            // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
            $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
            $res = json_decode($this->httpGet($url));
            $ticket = $res->ticket;
            if ($ticket) {
                $data->expire_time = time() + 7000;
                $data->jsapi_ticket = $ticket;
                $fp = fopen("jsapi_ticket.json", "w");
                fwrite($fp, json_encode($data));
                fclose($fp);
            }
        } else {
            $ticket = $data->jsapi_ticket;
        }
        return $ticket;
    }
    private function getAccessToken() {
        // access_token 应该全局存储与更新，以下代码以写入到文件中做示例
        $data = json_decode(file_get_contents("access_token.json"));
        if ($data->expire_time < time()) {
            // 如果是企业号用以下URL获取access_token
            // $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";
            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
            $res = json_decode($this->httpGet($url));
            $access_token = $res->access_token;
            if ($access_token) {
                $data->expire_time = time() + 7000;
                $data->access_token = $access_token;
                $fp = fopen("access_token.json", "w");
                fwrite($fp, json_encode($data));
                fclose($fp);
            }
        } else {
            $access_token = $data->access_token;
        }
        return $access_token;
    }
    private function httpGet($url) {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_TIMEOUT, 500);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_URL, $url);
        $res = curl_exec($curl);
        curl_close($curl);
        return $res;
    }
}

//demo
$url = $_GET['url'];
$appid = 'wx31d9cdb20bdcf15b';
$AppSecret = '1c99081b3b3ba17a7411778477720447';
$jssdk = new JSSDK($appid, $AppSecret, $url); //按照自己的公众号填写
$signPackage = $jssdk->GetSignPackage();
$tmp = json_encode(array('appId' => $signPackage["appId"], 'timestamp' => $signPackage["timestamp"], 'nonceStr' => $signPackage["nonceStr"], 'signature' => $signPackage["signature"], 'url' => $signPackage["url"]));
// $callback = $_GET['callback'];
// echo $callback . '(' . $tmp . ')';
echo $tmp;
exit;
?>